| /* Copyright (C) 1991, 1993, 1996, 1997 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Library General Public License as |
| published by the Free Software Foundation; either version 2 of the |
| License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with the GNU C Library; see the file COPYING.LIB. If not, |
| write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include <errno.h> |
| #include <stdio.h> |
| |
| |
| /* Push the character C back onto the input stream of STREAM. */ |
| int |
| ungetc (c, stream) |
| int c; |
| FILE *stream; |
| { |
| if (!__validfp (stream) || !stream->__mode.__read) |
| { |
| __set_errno (EINVAL); |
| return EOF; |
| } |
| |
| if (c == EOF) |
| return EOF; |
| |
| if (stream->__pushed_back) |
| /* There is already a char pushed back. */ |
| return EOF; |
| |
| if ((stream->__linebuf_active || stream->__put_limit > stream->__buffer) && |
| /* This is a read-write stream with something in its buffer. |
| Flush the stream. */ |
| __flshfp (stream, EOF) == EOF) |
| return EOF; |
| |
| stream->__pushback = (unsigned char) c; |
| /* Tell __fillbf we've pushed back a char. */ |
| stream->__pushed_back = 1; |
| stream->__pushback_bufp = stream->__bufp; |
| /* Make the next getc call __fillbf. It will return C. */ |
| stream->__bufp = stream->__get_limit; |
| |
| /* We just gave it another character to read, so it's not at EOF. */ |
| stream->__eof = 0; |
| |
| return stream->__pushback; |
| } |